The octanol–air equilibrium partition ratio (K_OA) is frequently used to describe the volatility of organic chemicals, whereby n-octanol serves as a substitute for a variety of organic phases ranging from organic matter in atmospheric particles and soils, to biological tissues such as plant foliage, fat, blood, and milk, and to polymeric sorbents. Because measured K_OA values exist for just over 500 compounds, most of which are nonpolar halogenated aromatics, there is a need for tools that can reliably predict this parameter for a wide range of organic molecules, ideally at different temperatures. The ability of five techniques, specifically polyparameter linear free energy relationships (ppLFERs) with either experimental or predicted solute descriptors, EPISuite's KOAWIN, COSMOtherm, and OPERA, to predict the K_OA of organic substances, either at 25 °C or at any temperature, was assessed by comparison with all K_OA values measured to date. In addition, three different ppLFER equations for K_OA were evaluated, and a new modified equation is proposed. A technique's performance was quantified with the mean absolute error (MAE), the root mean square error (RMSE), and the estimated uncertainty of future predicted values, that is, the prediction interval. We also considered each model's applicability domain and accessibility. With an RMSE of 0.37 and a MAE of 0.23 for predictions of log K_OA at 25 °C and RMSE of 0.32 and MAE of 0.21 for predictions made at any temperature, the ppLFER equation using experimental solute descriptors predicted the K_OA the best. Even if solute descriptors must be predicted in the absence of experimental values, ppLFERs are the preferred method, also because they are easy to use and freely available. Environ Toxicol Chem 2021;40:3166–3180. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

中文翻译：

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辛醇-空气分配比的可靠预测

辛醇-空气平衡分配比 ( K _OA ) 常用于描述有机化学品的挥发性，其中正辛醇可替代从大气颗粒和土壤中的有机物到生物组织等各种有机相如植物叶子、脂肪、血液和牛奶，以及聚合物吸附剂。因为测量了 K _OA仅存在 500 多种化合物的值，其中大多数是非极性卤代芳烃，因此需要能够可靠地预测各种有机分子的该参数的工具，理想情况下是在不同的温度下。五种技术的能力，特别是多参数线性自由能关系 (ppLFER) 与实验或预测的溶质描述符、EPISuite 的 KOAWIN、COSMOtherm 和 OPERA，预测有机物质在 25 °C 或任何温度下的K _{OA的能力，通过与迄今为止测量的所有}K _OA值进行比较来评估。此外，K _{OA的三个不同 ppLFER 方程}进行了评估，并提出了一个新的修正方程。一项技术的性能通过平均绝对误差 (MAE)、均方根误差 (RMSE) 和未来预测值的估计不确定性（即预测区间）来量化。我们还考虑了每个模型的适用范围和可访问性。RMSE 为 0.37，MAE 为 0.23，用于预测 25 °C 下的 log  K _OA，RMSE 为 0.32，MAE 为 0.21，用于在任何温度下进行预测，使用实验溶质描述符的 ppLFER 方程预测K _OA最佳。即使必须在没有实验值的情况下预测溶质描述符，ppLFER 也是首选方法，因为它们易于使用且免费提供。环境毒物化学2021；40:3166–3180。© 2021 作者。Wiley Periodicals LLC 代表 SETAC 出版的Environmental Toxicology and Chemistry 。